patch 8.1.2313: debugging where a delay comes from is not easy

Problem:    Debugging where a delay comes from is not easy.
Solution:   Use different values when calling ui_delay().
diff --git a/src/gui.c b/src/gui.c
index 53e073c..94a0503 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -279,7 +279,7 @@
 	}
 
 	if (pipe_error)
-	    ui_delay(300L, TRUE);
+	    ui_delay(301L, TRUE);
 
 	/* When swapping screens we may need to go to the next line, e.g.,
 	 * after a hit-enter prompt and using ":gui". */